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A. N. GOLDSMITH.

' METHfiD AND APPARATUS FOR TRANSMITTING SUSTAINE D WAVE SIGNALS.

APPLICAHON FILED JULY 29.1919.

mksg gfi Famed Oct. 17 1922.,

INVENTOR till n a e. e. talented trot. lid, 3 3am .5 y me ALFRED NQR'EON GGLDSTJLI'IH, GE NEW YORK, N. Y., ASSIG'JB-IGB, BY MESNE ASSIGN- IB'IENTS, TC RADIO fiQHPURATIOTrl Q1? All IX- IEIEIHQD "EUR TRAhlSl /LITTING SUSTAIIQL-n Application filed July $9,

1 "0 (ZZZ whom it may concern:

Be it known that l, ALFRED N. GOLDSMITH, a citizen oi. the United States, and a resident of t .e borough of ll-lanhattan, city, county, and State New Y rk, have invented certain new useful improvements in Methods and Apparatus for Transmitting Sustained Wave Signals, of which the following is a specification accompanied by drawings.

This invention relates to radio signaling, but more particularly to an improved method and apparatus of tone transmission from a sustained Wave generator. Ice sustained Wave transmitters protfecet signals consisting of constantamplitude radio frequency current, such signals are inaudible, (or practically so) in a receiving system having the usual rectifying detector, such as a crystal or v cuurn tube. Notwithstanding this fact, transmitters on ship board which may be called upon for distress signals, are compelled by law to be capable of radiating a signal Wave of such character that it is possible of reception and detection in such a simple detector of a receiving set.

It is accordingly highly desirable and even necessary to provide a method of controlling and modifying the sustained Wave radiation of an arc, alternator, oscillating vacuum tube, or other sustained Wave transmitter so that periodically modulated radiation is capable of being produced, that is, the amplitude of the radiation should be periodically Yaried at audio frequency.

In my copending application Serial #313,691, I have disclosed a method and apparatus for receiving sustained Wave signals in which. the energy modulated by periodically varying mutual inductance between primary and secondary coils acting as transformer in the circuits. in one of the preferred forms of the apparatus there dis closed. the modulator consists of a shield of conducting; material Which is interposed and Withdrawn between the primary and secondary transformer coils, thereby varying the mutual. field of said coils and producing; an audio frequency cycle in the circuits.

l have found that this method oi modulation may be advantageously applied to apparatus for transmitting; from a sustained wave generator, and by this means the desired results, with tone trans t'nission are ob- JitICA, A. CORPQEA'IIIQEI OF BELBRVARE.

WAVE SZGNAI LS.

Preferred forms of transmitting apparav tus for carrying out the method are illustrated in the accompanying drawings in which- Fig. 1 is a diagrammatic representation of circuits and apparatus for carrying out the invention;

Fig. 2 is a detail side View of the rotator of the modulator;

Fig. 3 is a diagrammatic view of a rnodification of the apparatus;

Fig. lis a detailside View partly broken away of the rotator in Fig. 3 showing; the relative arrangement of the coils;

Fig. 5 is a diagrammatic VlGW of another modification; and v Fig. 6 is a detail view artly broken away of the rotator in 5 snowing the relative arrangement of the coils.)

Referring to the drawings and first more particularly to Figs. 1 and il, A represents the antenna oi a transmitting station, grounded at B and having a variable loading coil C and antenna coupling coil 1). A transmitting'key C be provided in. any suitable location as shown. The primary circuit E includes the primary coupling coil l the variable condenser G, and in this instance the arc fed from a suitable source of direct current, as a generator J. Choke coils and other auxiliary equipment in the direct current leads are omitted the sake of simplicity.

'lhe coupling coils D and i forming a part or the modulator in: are preferably arranged substantially as indicated, which has been found to he a pract al Working arrangement, although they may be of any desired shape or construction. The shield of the modulator which is operatively connected to be periodically or intermittently interposed between the coils D and F, is shown in this instance as a toothed copper disk ll,

which may or may not be grounded as indicated at U. The disk L is conveniently mounted on the shaft P 01 a suitable motor Q; wh ch may conveniently be of variable speed, in such position that the teeth R pass between the coils D and F and these teeth are preferably of proper size and dimensions to substantially completely cover the aperture of the coils when registering tl srewith, as shown in side view in Q.

As the modulator disk L is rotated-be tween the coupling c ils D and F, the mutual inductance between the coils is periodically varied, in eilect coupling and de coupling the coils. By choosing a prpper number oi teeth on the disk or rotator L and a suitable running speed, radiation of my desired tone character isproduced and a note of any desired pitch may be obtained in the telephones at a receiving'station.

In those instances in which it is desirable to keep substantially constant load upon the radio frequency sustained wave generator, the modification shown in Figs. 3 and 4.- may be used. In said'figures the same rotator L acts to couple and decouple the coils ll and F and also, although independently, the coils S and '1, one of which, as the coil S is connected in an artificial antenna or absorbing circuit U having substantially the same constants as the actual antenna A, and the other coil T is connected in the primary circuit E". These coils S and T are arranged opposite each other as shown, but so spaced relatively to coils D and F, as shown in side view in Fig. l, that the separation between the respective pairs of coupling coils is an odd number of times the width of a tooth It on therotator L. l Vith this construction and arrangement, as coils D and Fare periodically and progressively coupled, the coils S and T will be periodically progressively but inversely! decoupled. The arc H will always be coupled either to the real antenna A. or the artificial antenna U, and as the arc is coupled to one of these antennae, it is synchronously decoupled from the other, so that the total load on the sustained wave generator remains substantially constant. k

In practicing my method w th the apparatus shown in Figs. 1 and 3, the wave length or frequency of the radiated wave may be slightly altered at audio frequency, due to-slight variations in inductance in the oscillating circuit of the arc, caused by the introduction of the teeth of the rotator L in the field of the coils. In the modification shown in Fig. 5, means are provided for maintaining the total inductance of the circuits substantially constant. in Fig. 5, auxiliary coils V and Vi in the antenna and primary circuits respectively, are so arranged that the rotator L passes through their field,

but these auxiliary coils are not coupled to a tooth R of the rotator L lies squarely between coils D and F air spaces are.directly opposite coils V and W, and vice versa. ,As the inductance of coils D and F is diminished by the introduction of a tooth R between them, the inductance of coils V and W is increased by an appreciable amount in synchronism therewith. The total inductance of coils D and V remains unchanged, as also does the total inductance of coils .F and WV, and the radiation, though variable in amplitude will not change in wave length.

Obviously the features shown in Figs. 3- and 5 may be combined in one system in any suitable and convenient manner well" under- '90' stood by those skilled in the art, so that both the total inductanceof the circuits and the load on the generator may be maintained substantially constant. L I claim and desire to obtain by Letters Patent the following: I i 1. In radio signaling, the method of transmitting sustained wave signals, which con sists in intermittently shielding the second ary from the primary coils acting as a trans- 1 former in the transmitting circuits, at a rate capable oi producing radiation of tonechar acter.

2. In radio signaling, the method of trans mitting sustained wave signals, which consists in intermittently! electro-magnetically shieldin the secondary from the primary of a trans .ormer in the transmitting circuits, at a rate capable of producing radiation of tone character.

3. In radio signaling, the method of transmitting'sustained wave signals, which coin sists in periodically varying the mutual inductance between coupling coils acting as a ice transformer in the primary and secondary transmitting circuits at a rate capable of producing radiation of tone character, while v maintaining substantially constant load on the source of sustained waves.

In radio signaling, the method of trans: mitting sustained wave signals, which consists in modulating the supplied energy by periodically varying the mutual field of coupling coils acting as a transformer in the primary and secondary transmitting circults at a rate capable of producing radiation of tone character, while maintaining substantially constant load on the source of sustained waves.

5. In apparatus for transmitting sustained wave signals, the combination of transmitting circuits, and means for modulating the supplied energy comprising coupling coils acting as a transformer in the transmitting circuits, and means for intermittently shielding the secondary from the primary coupling coil, at a rate capable ot' producing radiation of tone character.

6. In apparatus for transmitting sustained Wave signals, the combination of transmitting circuits, and means for modulating the supplied energy comprising coupling coils acting as a transformer in the transmitting circuits, and means for intermittently electro-magnetic'ally shielding the secondary from the primary coupling coil, at a rate capable of producing radiation of tone character.

7. ln apparatus for transmitting sustained Wave signals, the combination of transmitting circuits, and means for modulating the supplied energy comprising coupling co1ls acting as a transformer in the transmitting circuits, and means for intermittently. interposing a conducting medium between the coupling coils, at a rate capable of producing radiation of tone character.

8. In apparatus for transmitting sustained wave signals, the combination of transmitting circuits, and means for modulating the supplied energy comprising coupling coils acting as a transformer in the transmitting circuits, and means for intermittently interposing a short circuited secondary between the said coupling coils, at a rate capable of producing radiation of tone character.

9. ln apparatus for transmitting sustained Wave signals, the combination of transmitting circuits, and means for modulating the supplied energy comprising couping coils acting as a transformer in the transv mitting circuits, and means for periodi ally inserting and withdrawing shield. oi? corn ducting ma ingcoilu,

"t ucing radiation oi it). in apparatus for transmitting sustained wave signalsy the combination of transmitting circuits, and means for modulating the supplied energy comprisin coupling coils acting as a transformer in the transmitting circuits, and means for periodically varying the mutual inductance between said coupling coils at a rate capable of producing radiation of tone character, and means for maintaining the total inductance of the transmitting circuits substantially constant.

11. In apparatus for transmitting sustained Wave signals, the combination of transmitting circuits, and means tor modulating the supplied energy comprising coupling coils acting as a transformer in the trausmittingcircuits, and means for periodically varying the mutual field of said coupling coils at a rate capable of producing ra diation of tone character, and means for maintaining the total inductance of the transmitting circuits substantially constant, thereby producing radiation of tone character.

15%. In apparatus for transmitting sustained Wave signals, the combination with a source of sustained Waves, transmitting circuits, and means for modulating the sup plied energy comprising coupling coils acting as a transformer in the transmitting circuits, means for periodically varying the mutual inductance between said coupling coils at a rate capable of producing *adiation of tone character, and me; us for maintaining substantially constant load on the source of sustained waves.

13. In apparatus for transmitting sustained Wave signals, the comhinatioii of. a source of sustained. waves, transmitting circuits, and means for modulating the sup-' plied energy comprising coupling coils acting as a transformer in. the transmitting cir cuits, means for periodically varying the mutual field of said coupling coils, and means for maintaining substantially constant load on the source of sustained ll. in radio signaling, the method of tone transmission from. a sustained Wave generator, which consists in alternately dissipat ing the supplied energy outside thesignah ing circuits and releasing the supplied energy into the antenna circuit a rate caprble of producing radiation of tone character.

15. In radio signaling, the method of tone transmission from a sustained wave generator, which consists in alternately dissipat the supplied energy outside the signaliug circuits and releasingthe supplied en ergy into the antenna circijiit at rate caps ble of producing radiation of tone charact r: While maintaining the inductance of circuits substantially constant.

l6. in radio sigi nalin ,the method oi? tone transmission from a sulcflined Ware generator, which consists in. eriodicully ahsorhing and releasing the supplied energy at a rate capable of producing radiation of tone character, while maintaining substantially constant load on the sustained wave generator.

1?. in radio apparatus for tone transmission of sustained oscillations, the combinetion of a sustained Wave generator, transmitting circuits, and means for alternately dissipating the supplied energy outside the sig; naliug circuits and releasing the supp' energyet a rate capable of producing raoiation of tone character.

15%. in radio apparatus or tone transmission of sustained oscillations, the comhination of a sustained wave generator, transmitting circuits and means for rericdicallg.

lied

lit)

absorbing and releasing the supplied energy at a rate capable of producing radiation of tone character, and means for maintaining the total inductance of the circuits substantially constant.

19. in radio apparatus for tone transmission of sustained oscillations, the combination oi a sustained Wave generator,- trans-- mitting circuits, and means for periodically absorbing and releasing the supplied energy at a rate capable of producing radiation oi: tone character, and means for maintaining substantially constant load on the sustained wave generator.

20. In radio signaling, the method of tone transmission from a sustained Wave gene-r tor, which consists in periodically absorbing and releasing the supplied energy at a rate capable of producing radiation of tone character, While maintaining the total in ductance of the circuits and the load on the sustained Wave generator substantially constant.

21. In radio apparatus for tone transmission of sustained oscillations, the combination with an antenna, of a sustained. wave generator, transmitting circuits, means for periodically absorbing and releasing the supplied energy at a rate capable of producing adiation of tone character, means for maintaining the total inductance of the circuits substantially constant, and means for main-' taining substantially constant load on the sustained Wave generator.

22. l n apparatus for transmitting sustained Wave signals, the combination With transmitting circuit-s, coupling coils therein and a member having a plurality of conduct- .ing projections movable through the mutual lield of said coils at a frequency corresponding to that of an audible tone.

23. lln apparatus for transmitting su tained Wave signals, the combination of transmitting circuits, coupling coils therein and a member having a plurality of conducting projections rotatable through tlie i'nutual field of said coils at a frequency corresponding to that of an audible tone.

l n apparatus for transmitting sustained Wave signals, the combination of transmittin circuits, coupling coils therein and a Hat plate having a plurality of conducting projections movable through the mutual field of said co'ils at a frequency corr sponding to that of a;u audible tone.

In apparatus for transmitting sustained Wave signals, the combination of transmitting circuits, coaxial coupling coils therein and a member having a plurality of conducting projections rotatable about an axis parallel to the axis of the coils through th mutual field of said coils at a frequency corresponding to that of an audible tone.

26. in apparatus for transmitting susiaea iee .fiat conducting plate having a plurality of teeth rotatable between the coils at a frequency corresponding to thatof an audible tone.

28. in apparatus for transmitting sustained Wave signals, the combination of transmitting circuits, coupling coils therein and a member having a plurality of conduct- 1 ing projections movable between the coils, said coils and projections having areas of similar magnitudef 29. In apparatus for transmitting sustained wave signals, the combination of transmitting circuits and means for modu-d lating the sup-plied energy comprising coupling coils in the antenna and transmitting circuits and a grounded short circuited secondary adapted to be moved through the mutual field of said coils at a 't'requency corresponding to that of an audible tone.

30. in apparatus for transmitting sus tained *ave signals, the combination of transmitting circuits, coupling coils therein, an inductance coil in the antenna and an inductance coil in the t 'ansmitting circuit. said inductanccs beingin decoupled relation and a member having a plurality of conducting projections adapted to be alternately interposed at a frequency corresponding to that of an audible tone in the mutual field of the coupling coils and the self fields of the inductance coils.

31.111 apparatus for transmitting sustained wave signals, the combination of transmitting circuits, coupling coils therein, a second pair of coupling coils, one of which is connected in the transmitting circuits and,

the other in a loading circuit and a member havin a )lurallt i of conductin 'i)I0 ections :1 l l s adapted to be alternately interposed at a frequency corresponding to an audible tone in the mutual fields of said pairs ot coupling coils, whereby the antenna and loading circuit alternately absorb the supplied energy.

In testimony whereof l have signed this specification in the presence of two subscribing witnesses. I

ALFRED NORTON GOLDSMITH.

Witnesses CARL DREHER, I. MoCoMe. 

